signal 'unknown protocol'."
"That's pretty crude, even for a tracker, don't you think? And what about the time lag between question and response? If the tracker sees the reflection of its own signal and takes it for a response, the craft under interrogation has no 'thinking time'. Don't you think the tracker would notice that?" objected Steve.
"There are vast numbers of trackers, and so they are kept primitive due to cost considerations. Therefore, in designing the standard routines of trackers, they act on the principle 'the simpler the better', and don't bother to think about what else they could teach it just in case it might come in handy in the future. And what practical use is there in calculating the time lag between receipt of signal and response? Incidentally, the log ought to include both the interrogation and the response. Compare their binary structure," said Clive.
Steve commanded the computer to compare the two packets of data. The response was instantaneous: coincidence 99.998%.
Steve looked at Clive and spread his arms, smiling.
"The percentage of error could well be ascribed to errors in transmission."
"I think so too."
Steve looked at the protocol again. Something wasn't quite right.
"Hang on a minute, Clive. The laser reflection is precisely the same as the signal."
"Well, yes, it should be exactly the same."
"Oh? Are you sure?"
"We can assume it."
"And what about the Doppler effect?"
"What about it?"
"The reflector is moving away, yet we don't see any Doppler effect. How do you explain that?"
"If you think about it, the signal really ought to show some red shift. Here we don't see this. Wait, don't be hasty. Maybe we haven't taken something into account?" said Clive.
"Clive, your theory about the reflection has bitten the dust. I don't believe that a tracker can't distinguish its own signal from something else's. And then there's the Doppler effect, the object is undoubtedly sending signals! It's simply first making a correction for spectral shift," said Steve.
This thought had long been at the back of Steve's mind, he was simply reluctant to put it into words. Up to this moment. At first all this business about the manoeuvres, then slowing down in Saturn's atmosphere, the external appearance of the object, and for dessert, the Doppler effect too! The object was not of natural origin, it was a spaceship.
Clive was silent. Silence reigned.
"OK, let's take your theory as a starting point." Clive spoke in a quiet and unbelievably calm voice. "Two possibilities remain. The first is that it is military, fitted with all sorts of technology we civilians know nothing about. The second possibility is that we are dealing with an extraterrestrial civilisation. Frankly, I don't know which of the two is the crazier."
"Clive, there are no other possibilities!"
Steve extended his hand towards the monitor, which was still showing the photograph of the object. The photo was not crisp and detailed like movie alien spaceships, but dull, lacking contrast, quite ordinary.
"Do you really think asteroids look like that?" he asked Clive, pointing to the photograph.
"No, of course not," Clive replied.
"And can they accelerate to sub-light speeds, all on their own?"
"I agree with you."
They spent some time sitting in the semi-darkness of the hall, just staring at the image of the object on the auxiliary monitor.
"What now?" asked Clive.
"I think for a start we ought to consult Shelby," suggested Steve.
Clive unexpectedly burst out laughing.
"He must have a problem with his nerves," thought Steve, dumbfounded by such behaviour.
Clive, noticing Steve's reaction, laughed all the louder. He explained, smiling:
"No, Steve, I'm all right. I was just imagining you phoning Shelby and saying" - Clive continued in imitation of Steve's voice - "Mr. Shelby, could you come to the observatory? We've just found some aliens!"
"You're right, he wouldn't come alone, he'd bring a team of men in white coats with him," said Steve. Seeing the funny side of the situation, he laughed too.
"OK, joking aside, it's a serious matter. Call Shelby," said Steve.
"It's late, he'll be angry."
"You don't get angry about this sort of thing."
"That's true too," said Clive, and called Shelby's number.
After at least a dozen rings, the Dean's sleepy face appeared on the screen.
"Shelby here," said Shelby, sounding friendly enough in spite of the call at a clearly inappropriate time.
"Mr. Shelby, good evening, forgive me for calling so late," began Steve.
"Good evening? It's more like night... Not to worry. So what have you got there, lads?"
"Something very important has cropped up here. You will have to come to the observatory."
Steve paused briefly, then continued.
"You know we would not bother you at such a time for anything trivial. But this certainly isn't. We'll explain everything to you when you arrive."
The Dean's face instantly became serious. He obviously had a foreboding that something terrible had happened.
"Is it very bad?" he asked, in a quite different tone of voice.
"No, but it's important. Believe me, nothing terrible has happened, you may be sure."
"Understood, I'll come out." Shelby hung up before he had even finished the last word.
What is to be done?
More than half an hour had elapsed since the Dean had left home. For all this time, Steve and Clive had been combing through the observation logs for the entire history of the observatory. Had similar things happened in the past?
They didn't understand themselves why they were so feverishly looking for something that was certainly not there. Really each of them just wanted to be left on his own to think through what had happened. Could such awesome events really take place in such an everyday way, so boringly, so wearily? They sat in the dimly lit hall, it was long past midnight and they were exhausted. A normal long working day.
Suddenly an auxiliary monitor winked, drawing their attention. A message appeared on it saying that the gates to the observatory grounds had opened. "The visitor is registered as Mr. Shelby" was written under the image from the CCTV camera taken only a few seconds ago. In the photo, Shelby was just entering the observatory grounds. A few minutes later, the hall doors were flung open and Shelby walked in rapidly. Steve and Clive were already waiting for him at the door.
"What's up, lads?"
Steve moved an armchair towards him and Shelby obediently sat down. Steve and Clive drew up their own chairs and sat down after him.
"Mr. Shelby, I don't even know where to begin," Steve started, and then fell silent. He really didn't know where to begin. From the very beginning? Or should he just come out with it? Clive was no help, he was at a loss too.
"Take it easy, Steve, be so good as to bring a glass of cold water." Shelby quickly took the situation under control. He was once again the old man they knew so well. His voice sounded calming.
"Of course," replied Steve, then got up and went over to the mineral water machine. Pouring a glass, he returned to his chair.
"Here you are."
"Thank you, Steve. It's not for me, gulp down some of that cold water yourself," said Shelby, smiling.
Steve obediently did so. Amazingly, the tension simply vanished. Steve took another mouthful, not so hurriedly this time. The cold water ran down pleasantly to his stomach, spreading a pacifying calmness through his body. Shelby could relieve the tensest of situations with incredible ease. At the moment, he was just sitting opposite Steve and watching him.
"And now, lads, you can tell me what's going on," said Shelby. "Continue, Steve."
"Some time ago, we noticed a strange object beyond the bounds of the Solar System. This object was coming in from the outer depths of space, heading for the sun and intersecting the Earth's orbit. After being recorded by our te
lescope, the object accelerated, passed through the upper layers of Saturn's atmosphere, lost the greater part of its speed and was then caught by Jupiter's gravitational field. The object is now in orbit round Jupiter."
Shelby listened attentively, his face showing no trace of emotion. Thoughts were no doubt teeming in his head, but he gave no sign of it. He did not want to interrupt Steve, who took another gulp of water and continued.
"The object naturally interested us. We asked colleagues to take photos of the object. I refer to the Jupiter-Alpha team. They did so, but when they took the pictures, they used a laser range finder on the object and it sent a laser pulse in response..."
"Sent it or simply reflected it?" asked Shelby.
Clive came to life.
"No, it responded," he cut in.
Shelby nodded as a sign for Steve to continue, which he did.
"At first we thought it was an error, so we decided to check it ourselves. We sent the object's orbital parameters to one of our trackers, which took a bearing on the object. As you know, when a tracker takes a bearing, it requests the spacecraft's identification number."
"Yes, I know."
"So, the object really did respond. The tracker registered the response. The response was an exact copy of the interrogation." Steve paused, to allow Shelby the opportunity of asking about the reflection.
"And you're not confusing a response with a reflection?"
"Clive suggested that possibility too, but the point is that the pulse was shifted in spectrum. You see, at the moment the bearing was taken, the object was moving away from the tracker at cosmic velocity, so the reflected pulse should be somewhat different. The object corrected the spectral shift so that the tracker received an absolute copy of its own pulse. Sir, we think the object is the product of an extraterrestrial civilisation."
Shelby did not bat an eyelid as he received this information. He looked round the room over the heads of Clive and Steve while he immersed himself in thought for an instant. After a few seconds, Shelby asked:
"Are there no other possibilities?"
Clive and Steve simply shook their heads vigorously.
If they had been two first-year students, Shelby would have simply turned to the computers and it would have turned out ten minutes later that they had made a mistake due to an excess of romantic imagination and lack of sleep. But not Steve, and certainly not Clive, not by a long chalk! He knew these two.
"Show me the photos," Shelby said.
Steve signalled to Clive that he would make way for him. Clive thanked him with a nod. Without getting up from his chair, he moved it over to his console and began to work his magic there. A moment later, the photo of the object appeared on the large screen.
Shelby removed his spectacles, took a handkerchief out of his pocket and, without hurrying, wiped first one lens and then the other. He then put his spectacles back on and turned to look at the main screen. Steve, watching Shelby, could not help smiling at such moderation and self-control.
Shelby looked at the shot of the object for quite a long time. He then nodded in approval, and turned his gaze to the other screen, as if he had lost all interest. Taking off his glasses, he put them away in his front pocket.
"Well, I imagine you know the protocol in such cases. The confirmation of at least two independent groups is required. True, this is a special case, and I believe the military will have to be informed too, but otherwise we keep the information to ourselves. And first of all, to make certain, we must illuminate the object again, from another apparatus. We need a powerful laser with a good guidance system and a decent receiver. The craft on which the laser is mounted should not approach closely. Select the distance so that the object can be tracked easily without making it nervous by close contact. Do we have anything like that in this sector?" And without waiting for an answer, he added: "If not, let me know and I'll find one."
"The military?" asked Steve in surprise.
"Yes, but no-one else at all. I don't like it either, but I think we can't avoid it. What I'm afraid of is that they might notice